Microsoft Security Essentials MsMpEng.exe using high CPU Time
by Greg on Feb.01, 2010, under Antivirus, Security, Windows 7
I have Windows 7 Ultimate x64, but I think this might be problem in any version. I keep having issues with MsMpEng.exe hogging the cpu. Basically, using a large amount of resources, like 100%! It’s eating the CPU time and a lot of memory. The system will work just fine, even after running for hours, when suddenly the system slows to a crawl, almost to the point I have to reset the system. I finally narrowed the culprit to MsMpEng.exe, the scanner for MSSE (Microsoft Security Essentials).
Good news is, I think the cpu hog problem is solved! I found a link on a Google search about adding exclusions, which I suspected would be a problem for things like my backup programs. I added Crashplan and Syncback programs already, but what I found in that Google search was that you need to add the MSSE directories in C:\ProgramData to the exclusion list. WHAT!!??? Are you kidding me? MSSE doesn’t already exclude itself? Come on MS!! I really like MSSE, but that’s pretty stupid.
I went ahead and added these to MSSE exclusions:
C:\ProgramData\Microsoft\Microsoft Antimalware
C:\ProgramData\Microsoft\Microsoft Security Essentials
C:\Program Files\Microsoft Security Essentials
Now, for a couple days, I have had no more issues!!! We’ll see in a week if it really fixes it. That’s an easy fix, but completely annoying! I still like MSSE regardless. It’s not perfect, but I’d rather have it than anything else.
I am curious to know if anyone else found this fix to work?
Note: I do recommend people run a manual scan with MalwareBytes and SuperAntispyware once in a while, along with the real time scanner in MSSE. MSSE didn’t catch a recent trojan at one of my clients, same one was blocking MalwareBytes too. Only SuperAntispyware cleaned the system properly.
EDIT 02/10/2010:
It’s been about a week and a half, still working fine! It appears that this fixed the problem!
February 25th, 2010 on 1:07 pm
I tried your tweak that you mentioned and I really hope it will make a difference. Microsoft Security Essentials is a program with a good interface, however, the antimalware service executable is unforgivable. On a regular computer, it will hog the cpu when you are doing any task. Simply opening the explorer window will cause it to rise up to 6 percent and then back to zero.
Perhaps, your tweak might work because the program is updating itself? If the program is simultaneously updating its definitions and scanning its definitions, it might cause more cpu problems.
So far, there doesn’t seem to be any issue with this tweak. I’ll monitor the progress of the program for several days and conclude whether there is a difference.
February 25th, 2010 on 9:23 pm
Thanks for sharing your comments!
I hope that works for you too, and let me know how it works. The other day though, I ended up removing MSSE, because I kept having slow-downs on the system. MsMpEng.exe wasn’t hogging too much CPU, but it was still constantly working, and using around 20% and 120 or more Mb’s or RAM. I have a T9400 CPU and 4Gb’s of RAM, why is MSSE using so much though, and causing my system to hover around 20% CPU usage? I have it running on multiple systems, but just this bogs down my laptop.
Now, another process I have running and using a lot of time is CrashPlanService.exe. That’s my backup program, which I LOVE! and that hasn’t caused me any issues before, for over a year now. I even excluded that program and data files from MSSE in hopes that it wouldn’t conflict. So here’s the thing, I removed MSSE, and guess what? System hum’s along with very little CPU time. Maybe jumps around at 2% to 5%, with tiny bumps to 10 or 15% once in a while. That’s kind of normal, and the system moves along much more quickly. And yes, that’s with my backup program still running.
Anyway, hope you have better luck! I’d rather just not use AV than deal with the slow downs. Of course, I don’t think I’ve ever had a virus. Clean lots for my clients, but I know what *NOT* to do!
March 14th, 2010 on 9:04 am
I have Win7 Ultimate x86 and had the same issues as u guys. Added those directories into the exclusion list and voila – everything comes back to normal. Thanks!!
April 2nd, 2010 on 9:24 am
worked 100%. was experiencing high cpu usage from MSMPENG.exe Was watching results in resouce viewer (Vista), added those directories as mentioned. CPU and disk usage dropped to almost zero. Thank you very much.
April 2nd, 2010 on 9:07 pm
Greetings! I am trying your tweak on an XP machine. It appears one would need these paths for XP:
C:\Documents and Settings\All Users\Application Data\Microsoft\Microsoft Antimalware
and
C:\Documents and Settings\All Users\Application Data\Microsoft\Microsoft Security Essentials
Sound about right? Thanks for this info… very helpful indeed!
April 8th, 2010 on 10:40 am
I haven’t checked, but that does look correct for XP.
April 8th, 2010 on 12:03 pm
Hi there..I too am having trouble with this but when I opened up MSSE there are 3 different exclusions to pick from. I am not really a newbie but when it comes to these stuff I am. So my question:
Where the hec do I enter this stuff??…LOL
Please explain in layman terms. IE. go here then go here click on here click on there etc…
thanks a bunch.
April 9th, 2010 on 4:04 pm
by “c:\programdata” do you mean “C:\Documents and Settings\All Users\Application Data\Microsoft”? i run winxp and this is the only location i have “microsoft antimalware”.
@asshole (nice name!)
Yes, in vista/7 c:\programdata is a hidden/system folder where programs put settings and things, among other things. It used to be “C:\Documents and Settings\All Users\Application Data” in XP, yes.
April 9th, 2010 on 7:48 pm
@greg–(or whoever has the correct answer):
“…what I found in that Google search was that you need to add the MSSE directories in C:\ProgramData to the exclusion list. WHAT!!??? Are you kidding me? MSSE doesn’t already exclude itself? Come on MS!! I really like MSSE, but that’s pretty stupid.
I went ahead and added these to MSSE exclusions:
C:\ProgramData\Microsoft\Microsoft Antimalware
C:\ProgramData\Microsoft\Microsoft Security Essentials
C:\Program Files\Microsoft Security Essentials…”
When I open up MSSE, and go to the settings tab, in the box on left hand side there is a list to select from ie,Scheduled Scan, Default Action, Real-Time Protection etc…then there is these three: Excluded Files & locations, Excluded File Types, & Excluded processes….
My QUESTION is this: Where do I go to add the following–Is it within MSSE??–If not, where?:
C:\ProgramData\Microsoft\Microsoft Antimalware
C:\ProgramData\Microsoft\Microsoft Security Essentials
C:\Program Files\Microsoft Security Essentials
I’m sorry to sound so stupid but if you could just lead me in the right direction and tell me what to do step by step I would be forever grateful :)
Thanks in advance
Denise C.
April 11th, 2010 on 12:17 am
@Denise
Yes, in the Settings tab within MSSE. Click on the left “Excluded Files & Locations”, then add each of those paths to that list. (which is empty by default)
I hope this helps solve your issues. As of now, I’ve seen it fix a few systems, but not all. Probably because MSSE wasn’t really to blame, though it looked like it was. And I agree, its really stupid! If this truly is the case, that they don’t exclude from their own locations, or that MSSE is bogged down by accessing files in use by its own processes. However, not enough is known to say for sure. Maybe their program knows better even without the exclusions, we don’t know. But if it fixes even one system by adding them, I say try it! It can’t hurt! :)